JP2005189501A - Positive resist composition and pattern forming method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemically amplified resist composition suitable for use of an exposure light source of ≤250 nm, particularly F<SB>2</SB>excimer laser light (157 nm), and to more specifically provide a chemically amplified resist composition excellent in sensitivity and dissolution contrast when using a light source of 157 nm and improved in development defects and density distribution dependency, and a pattern forming method using the same. <P>SOLUTION: The positive resist composition contains (A) a resin which has fluorine atoms and is decomposed by the action of an acid to increase solubility in an alkaline developer and (B) a compound which generates an acid upon irradiation with actinic rays or radiation, wherein the compound (B) has a group which is decomposed by the action of an acid (acid decomposable group). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a chemically amplified resist composition suitably used in microlithography processes such as the production of VLSI and high-capacity microchips, and other photofabrication processes. More specifically, the present invention relates to a chemically amplified resist composition capable of forming a highly refined pattern using vacuum ultraviolet light of 160 nm or less.

  Integrated circuits have been increasingly integrated, and in manufacturing semiconductor substrates such as VLSI, processing of ultrafine patterns having a line width of less than a quarter micron has been required. As one of means for miniaturizing a pattern, it is known to shorten the wavelength of an exposure light source used in forming a resist pattern.

For example, in the manufacture of semiconductors with a degree of integration of 1 Gbit or more, the use of ArF excimer laser light (193 nm), which is a light source with a shorter wavelength in recent years, and F ₂ excimer to form a pattern of 0.1 μm or less. The use of laser light (157 nm) is being studied.

In accordance with the shortening of the wavelength of these light sources, the constituent components of the resist material and the compound structure thereof have also changed greatly.
Non-patent document 1 (Proc. SPIE. Vol. 3678, page 13) that the resin introduced with fluorine atoms (perfluoro structure) has sufficient transparency to 157 nm for F ₂ excimer laser light (157 nm). (1999)) and Non-Patent Document 2 (Proc. SPIE. Vol. 5039, page 93 (2003)), and an effective fluororesin structure is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2003-89708) and the like. Proposed resist compositions containing a fluorine-containing resin as a constituent have been studied.

However, conventional F ₂ excimer laser resists containing a fluorine atom-containing resin have had to increase the fluorine content in the resin in order to increase transparency, but as the fluorine content increases, the resist film becomes repellent. There was a problem that the development defects were increased due to water.
Furthermore, the conventional F ₂ excimer laser resist containing a fluorine atom-containing resin has room for improvement in terms of density dependency.

Patent Document 2 (Japanese Patent Laid-Open No. 7-324069) and Patent Document 3 (Japanese Patent Laid-Open No. 8-160606) disclose chemically amplified positive resist materials containing a sulfonium salt having an acid-decomposable group. Has been. However, in this publication, there is no improvement corresponding to the problems such as development defects and density dependency specific to the resist for F ₂ excimer laser containing the fluorine atom-containing resin.
JP 2003-89708 A JP 7-324069 A JP-A-8-160606 Proc. SPIE., 1999, 3678, 13 Proc. SPIE., 2003, 5039, 93

Accordingly, an object of the present invention is to provide a chemically amplified resist composition suitable for use as an exposure light source of 250 nm or less, particularly F ₂ excimer laser light (157 nm), specifically when using a light source of 157 nm. Excellent in sensitivity and dissolution contrast, development defects,
It is an object of the present invention to provide a chemically amplified resist composition having improved density dependency.

The inventors of the present invention have arrived at the present invention as a result of intensive investigations while paying attention to the above-mentioned characteristics.
That is, the present invention has the following configuration.

(1) A composition containing (A) a resin having a fluorine atom, which decomposes by the action of an acid and increases the solubility in an alkali developer, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation. A positive resist composition, wherein the compound (B) has a group (acid-decomposable group) that is decomposed by the action of an acid.
(2) The positive resist as described in (1) above, wherein the acid-decomposable group possessed by the compound (B) is any one of an ester group, an acetal group, a ketal group and a trimethylsilyl ether group. Composition.
(3) The positive resist composition as described in (1) above, which contains a compound represented by the following general formula (A), (B) or (C) as the compound (B).

In the above general formulas (A) to (C),
R ¹ represents an acid-decomposable group.
R ² represents an alkyl group, a cycloalkyl group or an aryl group.
R ³ represents an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group. At least two or more of R ³ may be bonded to form a ring structure.
R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an aryl group.
A ¹ represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group, an arylene group, or —O—R ⁶ —. R ⁶ represents an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.
A ² represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.
Y ¹ and Y ² each independently represents an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group. Y ¹ and Y ² may combine to form a ring.
Z ⁻ represents a counter anion.
n represents an integer of 1 to 3. m is 1 or 2. p represents an integer of 1 to 5. q represents an integer of 0 to 4. However, 0 <p + q ≦ 5.
(4) Any of (1) to (3), wherein the resin (A) contains at least one repeating unit represented by any one of the following general formulas (I) to (IV) The positive resist composition as described in 1. above.

In general formula (I),
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
Rk ₁ , Rk ₂ and Rk ₃ each independently represents a halogen atom, an alkyl group or an alkoxy group.
la represents an integer of 0 to 2, lb represents an integer of 0 to 6, and lc represents an integer of 0 to 6.
L ₁ represents a single bond or a divalent linking group.
n represents 0 or 1.
Y represents a hydrogen atom or an organic group.
In general formula (II),
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
R ₃₈ to R ₄₀ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group, an aryl group, an alkoxy group or an aralkyl group.
L ₂ represents a single bond, an oxygen atom, a sulfur atom or a divalent alkylene group.
Y represents a hydrogen atom or an organic group.
m and n each independently represents 0 or 1.
In general formula (III),
R _1a represents a hydrogen atom, a fluorine atom, a hydrogen atom, a bromine atom, a cyano group or a trifluoromethyl group.
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
Y represents a hydrogen atom or an organic group.
na represents an integer of 1 to 5. When na is 2 or more, two or more R _{11 to} R ₁₆ and Y may be the same or different.
In general formula (IV),
R ₂₃ , R ₂₄ and R ₂₅ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, a fluoroalkyl group or an alkoxy group.
Y represents a hydrogen atom or an organic group. n represents 0 or 1.
(5) A pattern forming method comprising: forming a resist film from the positive resist composition according to any one of (1) to (4) above; and exposing and developing the resist film.

According to the present invention, it becomes possible to provide a positive resist composition suitable for use with an exposure light source of 250 nm or less, particularly F ₂ excimer laser light (157 nm), specifically, the occurrence of development defects and scum is reduced, Furthermore, it is possible to provide a positive resist composition that is also excellent in defocus latitude.

Hereinafter, the present invention will be described in detail.
In addition, in the description of a group (atomic group) in this specification, the description which does not describe substituted and unsubstituted includes what has a substituent with what does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
In addition, -C (R ₁ ) (R ₂ ) (R ₃ ) or -C (R ₁ R ₂ R ₃ ) is such that each group represented by R _{1 to} R ₃ is bonded to a carbon atom by a single bond. Means a group.

[1] (A) Resin having fluorine atoms and decomposing by the action of an acid to increase the solubility in an alkaline developer The composition of the present invention has fluorine atoms and decomposes by the action of an acid. And a resin (hereinafter also referred to as a fluorine atom-containing resin (A)) whose solubility in an alkali developer is increased.
The fluorine atom-containing resin (A) is preferably 20 to 80 mol% of repeating units having 1 to 30 fluorine atoms, more preferably 3 to 18 fluorine atoms, based on all repeating units constituting the resin. More preferably, it contains 50-100 mol%.

The fluorine atom-containing resin (A) is a resin (acid-decomposable resin) that is decomposed by the action of an acid to increase the solubility in an alkali developer, and is a group (acid-decomposable) that decomposes by the action of an acid to generate an alkali-soluble group Group). Examples of the acid-decomposable group include those described as the acid-decomposable organic group as Y in the general formulas (I) to (IV) described later.
In the fluorine atom-containing resin (A), the total amount of repeating units having an acid-decomposable group is generally from 1 to 80 mol%, preferably from 3 to 70 mol, based on all repeating units constituting the resin. %.

  The fluorine atom-containing resin (A) preferably contains at least one repeating unit represented by the general formulas (I) to (IV) described above.

In general formula (I):
The fluoroalkyl group of R _{11 to} R ₁₆ refers to an alkyl group in which at least one hydrogen atom is fluorinated, preferably having 1 to 6 carbon atoms, and more preferably having 1 to 3 carbon atoms.
Specific examples of the fluoroalkyl group include, for example, a trifluoromethyl group, a difluoromethyl group, a fluoromethyl group, a pentafluoroethyl group, a 2,2,2-trifluoroethyl group, a 2-fluoroethyl group, 3, 3, A 3-trifluoropropyl group, a 3-fluoropropyl group, etc. can be mentioned. Particularly preferred is a trifluoromethyl group.
These fluoroalkyl groups may have a substituent, and examples of the substituent include a chlorine atom, a bromine atom, and an iodine atom.

Examples of the halogen atom for Rk ₁ , Rk ₂ and Rk ₃ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferred.
The alkyl group as Rk ₁ , Rk ₂ and Rk ₃ may have a substituent and is preferably an alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or an n-butyl group. , Sec-butyl group, t-butyl group and the like. The alkyl group of Rk ₁ , Rk ₂ and Rk ₃ is preferably an alkyl group substituted with a fluorine atom, and the carbon number thereof is 1 to 8, preferably 1 or 2, more preferably 1 carbon. . A perfluoroalkyl group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is preferred.
Alkoxy group Rk _1, Rk ₂ and Rk ₃ may have a substituent is preferably an alkoxy group having 1 to 8 carbon atoms, e.g., methoxy, ethoxy, propoxy, n- butoxy group Can be mentioned.
Examples of the substituent that the alkyl group and alkoxy group as Rk ₁ , Rk _2, and Rk ₃ may have include the same substituents as those described above as the substituent that each group may have. it can.

Rk ₁ , Rk ₂ and Rk ₃ are preferably a halogen atom or a fluorine-substituted alkyl group, particularly preferably a fluorine atom or a trifluoromethyl group.

  la represents an integer of 0 to 2, lb represents an integer of 0 to 6, lc represents an integer of 0 to 6, and la is preferably 0, lb is 0, and lc is an integer of 0 to 3.

Examples of the divalent linking group of L ₁ include an alkylene group, a cycloalkylene group, an alkenylene group, an arylene group, —O—, —S—, —O—R _22a —, —O—C (═O) —. R _22b —, —C (═O) —O—R _22c —, —C (═O) —N (R _22d ) —R _22e — and the like can be mentioned. R _22a , R _22b , R _22c and R _{22e each} may have a single bond or an ether group, an ester group, an amide group, a urethane group or a ureido group, a divalent alkylene group, a cycloalkylene group, an alkenylene. Represents a group or an arylene group. R _22d is a hydrogen atom or an alkyl group (preferably having 1 to 5 carbon atoms), a cycloalkyl group (preferably having 3 to 10 carbon atoms), an aralkyl group (preferably having 7 to 10 carbon atoms), or an aryl group (preferably carbon). Equations 6 to 10) are expressed.
The alkylene group is preferably a linear or branched alkylene group having 1 to 8 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and an octylene group.
The cycloalkylene group is preferably a cycloalkylene group having 5 to 12 carbon atoms, and examples thereof include monocyclic residues such as cyclopentylene group and cyclohexylene group, and polycyclic residues such as normolnan skeleton and adamantane skeleton. be able to.
The alkenylene group is preferably an alkenylene group having 2 to 6 carbon atoms, and examples thereof include an ethenylene group, a propenylene group, and a butenylene group.
The arylene group is preferably an arylene group having 6 to 15 carbon atoms, and examples thereof include a phenylene group, a tolylene group, and a naphthylene group.
Examples of the substituent that the divalent linking group of L ₁ may have include a halogen atom such as a fluorine atom and a chlorine atom, a cyano group, and the like, and a fluorine atom is preferable.

L ₁ is preferably a single bond, a methylene group or an —O— group.

  The organic group as Y includes both acid-decomposable and non-acid-decomposable ones, and preferably has 1 to 30 carbon atoms.

Examples of the acid-decomposable organic group for Y include —C (R _11a ) (R _12a ) (R _13a ), —C (R _14a ) (R _15a ) (OR _16a ), —X—COO—C ( R _11a ) (R _12a ) (R _13a ) and the like.
R _{11a to} R _13a and R _16a each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group.
R _14a and R _15a each independently represents a hydrogen atom or an alkyl group.
Two of R _11a , R _12a , and R _13a and two of R _14a , R _15a , and R _16a may be bonded to form a ring.
X represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.

As the alkyl group for R _{11a to} R _13a , R _14a , R _15a and R _16a , an alkyl group having 1 to 8 carbon atoms is preferable. For example, a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- A butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, etc. can be mentioned.
The cycloalkyl group for R _{11a to} R _13a and R _16a may have a substituent, and may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetracyclo group. A dodecyl group, an androstanyl group, etc. can be mentioned. A part of carbon atoms in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.

The aryl group of R _{11a to} R _13a and R _16a may have a substituent, and is preferably an aryl group having 6 to 10 carbon atoms. For example, a phenyl group, a tolyl group, a dimethylphenyl group, 2, A 4,6-trimethylphenyl group, a naphthyl group, an anthryl group, a 9,10-dimethoxyanthryl group, etc. can be mentioned.
The aralkyl group of R _{11a to} R _13a and R _16a may have a substituent and is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group. Can do.
The alkenyl group of R _{11a to} R _13a and R _16a may have a substituent, and is preferably an alkenyl group having 2 to 8 carbon atoms, such as a vinyl group, an allyl group, a butenyl group, or a cyclohexenyl group. Etc.
The substituents that R _{11a to} R _13a , R _14a , R _15a , and R _16a may have include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, and a hydroxy group. Carboxy group, halogen atom, alkoxy group, thioether group, acyl group, acyloxy group, alkoxycarbonyl group, cyano group, nitro group and the like.

Examples of the alkylene group for X include those having 1 to 8 carbon atoms such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and an octylene group.
Examples of the alkenylene group of X include those having 2 to 6 carbon atoms such as ethenylene group, propenylene group and butenylene group.
Examples of the cycloalkylene group represented by X include those having 5 to 8 carbon atoms such as a cyclopentylene group and a cyclohexylene group.
Examples of the arylene group for X include those having 6 to 15 carbon atoms such as a phenylene group, a tolylene group, and a naphthylene group.

  Preferred examples of the acid-decomposable group for Y include a t-butyl group, a t-amyl group, a 1-alkyl-1-cyclohexyl group, a 2-alkyl-2-adamantyl group, a 2-adamantyl-2-propyl group, Tertiary alkyl groups such as 2- (4-methylcyclohexyl) -2-propyl group, acetal groups such as 1-alkoxy-1-ethoxy group, 1-alkoxy-1-methoxy group and tetrahydropyranyl group, t-alkyl Preferred examples include a carbonyl group and a t-alkylcarbonylmethyl group.

The non-acid-decomposable organic group of Y is an organic group that is not decomposed by the action of an acid. For example, an alkyl group, a cycloalkyl group, an aryl group that is not decomposed by the action of an acid,
Examples thereof include an aralkyl group, an alkoxy group, an alkoxycarbonyl group, an amide group, and a cyano group. The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, or a 2-ethylhexyl group. And octyl group. The cycloalkyl group preferably has 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and an adamantyl group. The aryl group is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group. The aralkyl group is preferably an aralkyl group having 6 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a cumyl group. The alkoxy group in the alkoxy group and the alkoxycarbonyl group is preferably an alkoxy group having 1 to 5 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, and an isobutoxy group.

  Although the preferable specific example of the repeating unit shown by general formula (I) below is given, it is not limited to these.

In general formula (II):
The fluoroalkyl group R ₁₁ to R _16, include the same fluoroalkyl groups as R ₁₁ to R ₁₆ in formula (I).
Examples of the alkyl group of R _{38 to} R ₄₀ include the same alkyl groups as Rk ₁ in the general formula (I) described above.
The aryl group of R _{38 to} R ₄₀ is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, tolyl group, dimethylphenyl group, 2,4,6-trimethylphenyl group, naphthyl group, anthryl group. , 9,10-dimethoxyanthryl group and the like.
Examples of the alkoxy group of R _{38 to} R ₄₀ include the same alkoxy groups as Rk ₁ in the general formula (I).
The aralkyl group of R _{38 to} R ₄₀ is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.
Examples of the divalent alkylene group represented by L ₂ include the same divalent alkylene groups as L ₁ in the general formula (I).
Examples of the organic group for Y include the same organic groups as Y in the general formula (I).

  Preferred specific examples of the repeating unit represented by the general formula (II) include the following:

In general formula (III),
The fluoroalkyl group R ₁₁ to R _16, include the same fluoroalkyl groups as R ₁₁ to R ₁₆ in formula (I).
Examples of the organic group for Y include the same organic groups as Y in the general formula (I).

  Hereinafter, although the specific example of the repeating unit represented by general formula (III) is given, it is not limited to these.

In general formula (IV):
Examples of the alkyl group of R _{23 to} R ₂₅ include the same alkyl groups as Rk ₁ in the general formula (I) described above.
Examples of the fluoroalkyl group of R _{23 to} R ₂₅ include the same fluoroalkyl groups as R _{11 to} R ₁₆ in the general formula (I) described above.
Examples of the alkoxy group of R _{23 to} R ₂₅ include the same alkoxy groups as Rk ₁ in the general formula (I) described above.
Examples of the organic group for Y include the same organic groups as Y in the general formula (I).

  Hereinafter, although the specific example of the repeating unit represented by general formula (IV) is given, it is not limited to these.

  Further, the fluorine atom-containing resin (A) was copolymerized with the repeating units represented by the following general formulas (V) to (IX) in addition to the repeating units represented by the general formulas (I) to (IV). A resin is more preferable.

In general formulas (V) to (VII),
R ₀ and R _{1 each} represents a hydrogen atom, a fluorine atom, an alkyl group, a fluoroalkyl group, a cycloalkyl group or an aryl group.
R _{2 to} R _{4 each} represents an alkyl group, a fluoroalkyl group, a cycloalkyl group, or an aryl group. R ₀ and R ₁ , R ₀ and R ₂ , R ₃ and R ₄ may combine to form a ring.

In general formula (VIII),
Rx ₁ to Rx ₁ each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a fluoroalkyl group.
R ^a and R ^b each independently represent a hydrogen atom, —C (R ₁₁ R ₁₂ R ₁₃ ). R ₁₁ , R ₁₂ and R ₁₃ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group.
R _{17 to} R ₂₂ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{17 to} R ₂₂ represents a fluorine atom or a fluoroalkyl group.
Z ₁ represents a single bond, an alkylene group, a cycloalkylene group, or an arylene group. Preferred substituents include a halogen atom, a hydroxyl group, an alkoxy group, and a cyano group. Particularly preferred are a fluorine atom and a hydroxyl group, and a fluorine atom is even more preferred. If Z ₁ is a fluorine atom as a substituent, the number of fluorine atoms is preferably 1-5, more preferably 1-3.
L ₁ represents a single bond or a divalent linking group.
n and q each independently represents 0 or 1.
r represents an integer of 1 to 6.
Y represents a hydrogen atom or an organic group.

In general formula (IX),
R ₂₆ and R ₂₇ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, or a fluoroalkyl group.
Y represents a hydrogen atom or an organic group.

In general formulas (V) to (VII),
Examples of the fluoroalkyl group of R _{0 to} R ₄ include the same fluoroalkyl groups as R _{11 to} R ₁₆ in the general formula (I) described above.
The cycloalkyl group represented by R _{0 to} R ₄ may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetracyclo group. A dodecyl group, an androstanyl group, etc. can be mentioned. A part of carbon atoms in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.
The aryl group of R _{0 to} R ₄ may have a substituent, and is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, a dimethylphenyl group, 2,4,6- Examples thereof include a trimethylphenyl group, a naphthyl group, an anthryl group, and a 9,10-dimethoxyanthryl group.

  Hereinafter, although the specific example of the repeating unit represented by general formula (V)-(VII) is given, it is not limited to these.

In general formula (VIII):
Examples of the fluoroalkyl group of Rx _{1 to} Rx ₃ and R _{11 to} R ₂₂ include the same fluoroalkyl groups as R _{11 to} R ₁₆ in the general formula (I) described above.
As the alkylene group for Z _1, the same divalent alkylene groups as L ₁ in the above general formula (I) can be exemplified.
The cycloalkylene group for Z ₁ may be monocyclic or polycyclic. Examples of the substituent include a hydroxyl group, an alkyl group, an alkoxy group, a halogen atom, and a cyano group. The monocyclic type preferably has 3 to 8 carbon atoms, and examples thereof include a cyclopropylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, and a cyclooctylene group. The polycyclic type has 6 to 20 carbon atoms, such as adamantyl residue, norbornyl residue, isobornyl residue, camphanyl residue, dicyclopentyl residue, α-pinel residue, tricyclodecanyl residue. Preferred examples include a group, a tetracyclododecyl residue, an androstanyl residue and the like. However, the carbon atom in the monocyclic or polycyclic cycloalkyl group may be substituted with a heteroatom such as an oxygen atom. As the substituent of the cycloalkylene group, a fluorine atom is preferable. As the cycloalkylene group substituted with a fluorine atom (a cycloalkylene group in which at least one hydrogen atom is substituted with a fluorine atom), for example, a perfluorocyclopropylene group Perfluorocyclopentylene group, perfluorocyclohexylene group, perfluorocycloheptylene group, perfluorocyclooctylene group and the like.
As the arylene group for Z _1, an arylene group having 4 to 20 carbon atoms is preferable, and examples thereof include a phenylene group, a tolylene group, and a naphthylene group.
As the divalent linking group represented by L _1, can be the same as the divalent linking group as L ₁ in formula (I).
Examples of the organic group for Y include the same organic groups as Y in the general formula (I) described above.

  Hereinafter, although the specific example of the repeating unit represented by general formula (VIII) is given, it is not limited to these.

In general formula (IX),
Examples of the alkyl group for R ₂₆ and R ₂₇ include the same alkyl groups as Rk ₁ in the general formula (I) described above.
Examples of the fluoroalkyl group represented by R ₂₆ and R ₂₇ include the same fluoroalkyl groups as R _{11 to} R ₁₆ in the general formula (I) described above.
Examples of the organic group for Y include the same organic groups as Y in the general formula (I).

  Hereinafter, although the specific example of the repeating unit represented by general formula (IX) is given, it is not limited to these.

The fluorine atom-containing resin (A) used in the present invention can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, monomer species are charged into a reaction vessel in a batch or in the course of reaction, and if necessary, a reaction solvent such as ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, methyl ethyl ketone, A ketone such as methyl isobutyl ketone, an ester solvent such as ethyl acetate, and the composition of the present invention such as propylene glycol monomethyl ether acetate described below are dissolved in a solvent that dissolves uniformly and then nitrogen, argon, etc. Polymerization is started using a commercially available radical initiator (azo initiator, peroxide, etc.) as necessary under an inert gas atmosphere. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery.
The concentration of the reaction is usually 20% by mass or more, preferably 30% by mass or more, and more preferably 40% by mass or more. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 50 to 100 ° C.

The repeating structural units represented by the specific examples may be used singly or in combination.
In the present invention, the fluorine atom-containing resin may be used alone or in combination.

The content of the repeating structural units represented by the above general formulas (I) to (IV) is generally 20 to 80 mol%, preferably 30 to 70 mol%.
Further, the content of the repeating structural units represented by the general formulas (V) to (IX) is generally 10 to 80 mol%, preferably 20 to 70 mol%.

The weight average molecular weight of the fluorine atom-containing resin (A) is 1,000 to 200,000 as a polystyrene conversion value by the GPC method, and when it is 1,000 or more, the heat resistance and dry etching resistance are excellent. It is excellent in film forming property as it is the following. More preferably, it is 3,000-20,000.
The molecular weight distribution (Mw / Mn) is usually 1 to 10, preferably 1 to 5, and more preferably 1 to 4. The smaller the molecular weight distribution, the smoother the resolution, the resist shape, and the side wall of the resist pattern, and the better the roughness.

  In the positive resist composition of the present invention, the blending amount of all the resins (A) according to the present invention in the entire composition is preferably 40 to 99.99% by mass, more preferably 50 to 50% in the total resist solid content. It is 99.97 mass%.

[2] (B) Compound that generates acid upon irradiation with actinic ray or radiation (photoacid generator)
The composition of the present invention includes a compound (hereinafter referred to as an acid generator) that generates an acid upon irradiation with actinic rays or radiation, and further has a group (acid-decomposable group) that decomposes in the molecule by the action of an acid. (Referred to as (B1)). Among them, when the acid generator (B1) has an ester group, an acetal group, a ketal group, or a trimethylsilyl ether group as the acid-decomposable group, it is excellent in the effect of reducing development defects and density dependency. It is preferable.
Furthermore, the onium salt containing an acid-decomposable ester group represented by the following general formulas (A) to (C) is decomposed by the action of an acid in the exposed region, and has high acidity and alkali solubility. Since excellent carboxylic acid is generated, the effect of dissolution contrast is excellent, and it is more preferable.

In the above general formulas (A) to (C),
R ¹ represents an acid-decomposable group.
R ² represents an alkyl group, a cycloalkyl group or an aryl group.
R ³ represents an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group. At least two or more of R ₃ may be bonded to form a ring structure.
R ⁴ and R ⁵ represent a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an aryl group.
A ¹ represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group, an arylene group, or —O—R ⁶ —. R ⁶ represents an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.
A ² represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.
Y ¹ and Y ² represent an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group. Y ¹ and Y ² may combine to form a ring.
Z ⁻ represents a counter anion.
n represents an integer of 1 to 3. m is 1 or 2. p represents an integer of 1 to 5. q represents an integer of 0 to 4. However, 0 <p + q ≦ 5.

The acid-decomposable group for R ¹ is preferably one having 3 to 30 carbon atoms, and is the same as the acid-decomposable organic group as Y in the general formula (I) used in the detailed description of the resin described above. You can list things.

Preferable specific examples of the acid-decomposable group for R ¹ include a t-butyl group, a t-amyl group, a 1-alkyl-1-cyclohexyl group, a 2-alkyl-2-adamantyl group, and a 2-adamantyl-2-propyl group. A tertiary alkyl group such as 2- (4-methylcyclohexyl) -2-propyl group, an acetal group such as 1-alkoxy-1-ethoxy group, 1-alkoxy-1-methoxy group and tetrahydropyranyl group, t- Preferred examples include an alkylcarbonyl group and a t-alkylcarbonylmethyl group.

As the alkyl group for R ^{2 to} R ⁵ , Y ¹ , and Y ² , an alkyl group having 1 to 8 carbon atoms is preferable. For example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, A hexyl group, 2-ethylhexyl group, an octyl group, etc. can be mentioned.

The cycloalkyl group of R ^{2 to} R ⁵ , Y ¹ and Y ² may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetracyclo group. A dodecyl group, an androstanyl group, etc. can be mentioned. A part of carbon atoms in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.

The aryl group for R ^{2 to} R ⁵ , Y ¹ , and Y ² may have a substituent and is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, and a dimethylphenyl group. 2,4,6-trimethylphenyl group, naphthyl group, anthryl group, 9,10-dimethoxyanthryl group, and the like.
The aralkyl group of Y ¹ and Y ² may have a substituent, and is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.

The alkoxy group for R ³ may have a substituent and is preferably an alkoxy group having 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, and an n-butoxy group. .

As the alkyloxycarbonyl group for R ³ , an alkyloxycarbonyl group having 1 to 8 carbon atoms is preferable. For example, a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an n-butoxycarbonyl group, a sec-butoxycarbonyl group, A hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, octyloxycarbonyl group, etc. can be mentioned.

The alkylene group for A ¹ , A ² , and R ⁶ is preferably a linear or branched alkylene group having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, or an octylene group. Etc.
The cycloalkylene group represented by A ¹ , A ² , or R ⁶ is preferably a cycloalkylene group having 5 to 12 carbon atoms, such as a monocyclic residue such as a cyclopentylene group or a cyclohexylene group, a normornan skeleton, an adamantane skeleton, etc. And polycyclic residues.
The alkenylene group of A ¹ , A ² , and R ⁶ is preferably an alkenylene group having 2 to 6 carbon atoms, and examples thereof include an ethenylene group, a propenylene group, and a butenylene group.
The arylene group of A ¹ , A ² , and R ⁶ is preferably an arylene group having 6 to 15 carbon atoms, and examples thereof include a phenylene group, a tolylene group, and a naphthylene group.

  Examples of the substituent that each of the above groups may have include, for example, a hydroxyl group, a halogen atom (fluorine, chlorine, bromine, iodine), a nitro group, a cyano group, the above alkyl group, a methoxy group, an ethoxy group, and a hydroxyethoxy group. Group, propoxy group, hydroxypropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, alkoxy group such as t-butoxy group, alkoxycarbonyl group such as methoxycarbonyl group, ethoxycarbonyl group, benzyl group, phenethyl group, Aralkyl groups such as cumyl groups, aralkyloxy groups, formyl groups, acetyl groups, butyryl groups, benzoyl groups, acyl groups such as cyanamyl groups, valeryl groups, acyloxy groups such as butyryloxy groups, alkenyl groups, vinyloxy groups, propenyloxy groups, Alkenyl groups such as allyloxy and butenyloxy groups Shi group, an aryl group, an aryloxy group such as phenoxy group, and an aryloxycarbonyl group such as benzoyloxy group.

Examples of counter anions of Z ⁻ include perfluoroalkanesulfonic acid anions such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , and pentafluoro Examples include, but are not limited to, condensed polynuclear aromatic sulfonate anions such as benzenesulfonate anion and naphthalene-1-sulfonate anion, anthraquinone sulfonate anion, and sulfonate group-containing dyes.

  Specific examples of the compound represented by formula (A) are shown below, but the present invention is not limited thereto.

  Specific examples of the compound represented by the general formula (B) are shown below, but the present invention is not limited thereto.

Specific examples of the compound represented by the general formula (C) are shown below, but the present invention is not limited thereto.

  Specific examples of the acid generator (B1) that can be used in the present invention other than the compounds represented by the general formulas (A) to (C) are shown below, but the present invention is not limited thereto.

The acid generator (B1) can be synthesized, for example, according to the methods described in JP-A-7-324069 and JP-A-8-160606.
The addition amount of the acid generator (B1) is preferably 0.1 to 15% by mass, more preferably 0.5 to 9% by mass, and still more preferably 1 to 5%, based on the solid content of the resist composition as a total amount. 5.5% by mass.

As the acid generator used in the present invention, an acid generator (B1) having a group capable of decomposing by the action of an acid to generate a carboxyl group in its molecule is generally used as a light generator. A known compound used as an acid generator (hereinafter referred to as an acid generator (B2)) can be mixed and used.
Commonly used acid generators (B2) are, for example, photoinitiators for photocationic polymerization, photoinitiators for radical photopolymerization, photodecolorants for dyes, photochromic agents, microresists, etc. Known light (400-200 nm ultraviolet light, far ultraviolet light, particularly preferably g-line, h-line, i-line, KrF excimer laser light), ArF excimer laser light, F ₂ excimer laser light, electron beam , An X-ray, a molecular beam, an ion beam or the like, or a compound capable of generating an acid upon irradiation with radiation.

For example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metal / organic halides, acid generators having o-nitrobenzyl type protecting groups And compounds capable of generating sulfonic acid by photolysis represented by imino sulfonate and the like, and disulfone compounds.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407, JP 63-26653, JP 55-164824, JP 62-69263, JP 63-146038, JP 63-163452, JP 62-153853, JP 63- The compounds described in No. 146029 and the like can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  Among the acid generators (B2), those that are particularly effectively used will be described below.

  (1) An iodonium salt represented by the following general formula (PAG1) or a sulfonium salt represented by the general formula (PAG2).

Ar ¹ and Ar ² each independently represents an aryl group. The aryl group may have a substituent, and preferred substituents include alkyl groups (preferably haloalkyl groups as substituted alkyl groups), cycloalkyl groups, aryl groups, alkoxy groups, nitro groups, carboxyl groups, alkoxy groups. Examples include a carbonyl group, a hydroxy group, a mercapto group, and a halogen atom.

R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² each independently represents an alkyl group, a cycloalkyl group or an aryl group. Preferred are aryl groups having 6 to 14 carbon atoms, alkyl groups and cycloalkyl groups having 1 to 8 carbon atoms, and substituted derivatives thereof.
Preferred substituents are an aryl group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group, and a halogen atom. An alkoxy group having 1 to 8 carbon atoms, a carboxyl group, and an alkoxycarbonyl group;

Z ⁻ represents a counter anion, such as perfluoroalkanesulfonic acid anion such as BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , pentafluoro Examples include, but are not limited to, condensed polynuclear aromatic sulfonate anions such as benzenesulfonate anion and naphthalene-1-sulfonate anion, anthraquinone sulfonate anion, and sulfonate group-containing dyes.

Two of R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² , and Ar ¹ and Ar ² may be bonded via a single bond or a substituent.

  Specific examples include the following compounds, but are not limited thereto.

  Diphenyl iodonium dodecyl benzene sulfonate, diphenyl iodonium trifluoromethane sulfonate, bis (4-trifluoromethylphenyl) iodonium trifluoromethane sulfonate, bis (4-t-butylphenyl) iodonium camphor sulfonate.

  Triphenylsulfonium dodecylbenzenesulfonate, triphenylsulfonium-2,4,6-trimethylbenzenesulfonate, triphenylsulfonium-2,4,6-triisopropylbenzenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctanesulfonate , Triphenylsulfonium perfluorononane sulfonate, triphenylsulfonium camphor sulfonate, triphenylsulfonium perfluorobenzene sulfonate, triphenylsulfonium-3,4-bis (trifluoromethyl) benzene sulfonate.

  The above onium salts represented by the general formula (PAG1) or (PAG2) are known and can be synthesized, for example, by the methods described in U.S. Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101,331.

  (2) A disulfone derivative represented by the following general formula (PAG3) or an iminosulfonate derivative represented by the general formula (PAG4).

Ar ³ and Ar ⁴ each independently represents an aryl group.
R ¹⁰³ represents an alkyl group, a cycloalkyl group or an aryl group. A represents an alkylene group, an alkenylene group or an arylene group.
Specific examples include the following compounds, but are not limited thereto.

  Bis (tolyl) disulfone, bis (4-methoxyphenyl) disulfone, bis (4-trifluoromethylphenyl) disulfone, phenyl-4-isopropylphenyldisulfone.

  (3) A diazodisulfone derivative represented by the following general formula (PAG5).

Here, R ¹⁰⁴ and R ¹⁰⁵ each independently represents an alkyl group, a cycloalkyl group, or an aryl group.
Specific examples include the following compounds, but are not limited thereto.

  Bis (phenylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (tolylsulfonyl) diazomethane, bis (t-butylsulfonyl) diazomethane.

  (4) As the acid generator (B2), a phenacylsulfonium derivative represented by the following general formula (PAG6) can also be used.

In general formula (PAG6),
R _{1 to} R ₅ represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group, and at least two of R _{1 to} R ₅ are bonded. To form a ring structure.
R ₆ and R ₇ represent a hydrogen atom, an alkyl group, an alkyl group, a cyano group, or an aryl group.
Y ₁ and Y ₂ represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an aromatic group containing a hetero atom, and Y ₁ and Y ₂ may be bonded to form a ring.
Y ₃ represents a single bond or a divalent linking group.
X ⁻ represents a non-nucleophilic anion.
At least one of R ₁ to R ₅ and at least one of Y ₁ or Y ₂ may be bonded to form a ring, or at least one of R ₁ to R ₅ and at least one of R ₆ or R ₇ may be bonded. To form a ring.
It may be bonded via a linking group at any position of R ₁ to R ₇ or at any position of Y ₁ or Y ₂ and may have two or more structures of the formula (PAG6).

  Specific examples of the compound represented by the above formula (PAG6) are shown below, but the present invention is not limited thereto.

  Hereinafter, preferred compounds (B2) that generate an acid upon decomposition by irradiation with actinic rays or radiation are shown.

  When the acid generator (B2) is used in combination with the acid generator (B1), the molar ratio of the acid generator (B1) to the acid generator (B2) is (B1) :( B2) = 90: 10-30: The range of 70 is preferable, and (B1) :( B2) = 80: 20 to 60:40 is more preferable.

[4] Fluorine-based and / or silicon-based surfactant The positive resist composition of the present invention further comprises a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based surfactant, fluorine atom and It is preferable that one or two or more surfactants containing both silicon atoms are contained.
When the positive resist composition of the present invention contains the surfactant, it is possible to provide a resist pattern with good sensitivity and resolution and with less adhesion and development defects.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540 No. 7, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A 2002-277862, US Pat. No. 5,405,720. , No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,543,098, No. 5,576,143, No. 5,294,511, No. 5,824,451. The following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block linked body) or a poly (block linked body of oxyethylene and oxypropylene) group, may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates). Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive resist composition (excluding the solvent).

[5] Acid Diffusion Inhibitor The composition of the present invention includes performance variations (pattern T-top shape formation, sensitivity variations, pattern line width variations, etc.) over time after irradiation with actinic rays or radiation until heat treatment. It is preferable to add an acid diffusion inhibitor for the purpose of preventing performance fluctuation due to aging after coating, and further, after irradiation with actinic rays or radiation, excessive diffusion of acid (degradation of resolution) during heat treatment. The acid diffusion inhibitor is an organic basic compound, for example, an organic basic compound containing basic nitrogen, and a compound having a pKa value of the conjugate acid of 4 or more is preferably used.
Specifically, the structures of the following formulas (A) to (E) can be exemplified.

Here, R ²⁰⁰ , R ^201, and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or 6 to 20 carbon atoms. Wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms and a hydroxyalkyl group having 1 to 20 carbon atoms. Examples of the cycloalkyl group having a substituent include 3 to 3 carbon atoms. Examples thereof include 20 aminocycloalkyl groups and 3 to 20 hydroxycycloalkyl groups. R ²⁰³ R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
Further preferred compounds are nitrogen-containing basic compounds having two or more nitrogen atoms of different chemical environments in one molecule, and particularly preferably both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group.

  Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, imidazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and the like. These may have a substituent, and preferred substituents include amino, aminoalkyl, alkylamino, aminoaryl, arylamino, alkyl, alkoxy, acyl, acyloxy, aryl Group, aryloxy group, nitro group, hydroxyl group, cyano group and the like.

Particularly preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,
3, -tetramethylanidin, imidazole, 2-methylimidazole, 4-methylimidazole, N-methylimidazole, 2-phenylimidazole, 4,5-diphenylimidazole, 2,4,5-triphenylimidazole, 2-amino Pyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino- 4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4-aminoethylpyridine,

  3-aminopyrrolidine, piperazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl)- Examples include 5-methylpyrazine, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine. However, the present invention is not limited to this. These nitrogen-containing basic compounds are used alone or in combination of two or more.

  The use ratio of the acid generator and the organic basic compound in the composition is preferably (acid generator) / (organic basic compound) (molar ratio) = 2.5 to 300. By setting the molar ratio to 2.5 or more, high sensitivity is obtained, and by setting the molar ratio to 300 or less, it is possible to reduce the thickness of the resist pattern over time until post-exposure heat treatment and improve resolution. . (Acid generator) / (organic basic compound) (molar ratio) is preferably 5.0 to 200, more preferably 7.0 to 150.

[6] Solvent The composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. Examples of the solvent used here include 1-methoxy-2-propanol acetate (propylene glycol monomethyl ether acetate), 1-methoxy-2-propanol (propylene glycol monomethyl ether), ethylene dichloride, cyclohexanone, cyclopentanone, and 2-heptanone. , Γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, toluene, Ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate Ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like are preferable, 1-methoxy-2-propanol acetate, 1-methoxy- 2-propanol is particularly preferred. These solvents are used alone or in combination. When mixed and used, those containing 1-methoxy-2-propanol acetate or those containing 1-methoxy-2-propanol are preferred.

[7] Non-polymer type dissolution inhibitor The positive resist composition of the present invention preferably further contains a non-polymer type dissolution inhibitor. Here, the non-polymer type dissolution inhibitor is a compound having a molecular weight of usually 3000 or less, preferably 200 to 3000, in which at least two acid-decomposable groups are present, and the solubility in an alkali developer is caused by the action of an acid. It is a compound that increases. In particular, it is preferable from the viewpoint of transparency that a fluorine atom is substituted in the mother nucleus. The addition amount is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, and further preferably 7 to 7% by mass with respect to the polymer in the composition.
30% by mass. Addition of a non-polymer type dissolution inhibitor further improves sensitivity and contrast.

  Specific examples of the non-polymer type dissolution inhibitor are shown below, but the present invention is not limited to these specific examples.

  In the manufacture of precision integrated circuit elements, the pattern forming process on the resist film is carried out by applying the positive resist composition of the present invention on a substrate (eg, a transparent substrate such as a silicon / silicon dioxide covering, a glass substrate, an ITO substrate). A good resist pattern can be formed by applying an object, forming a resist film, and then irradiating with an actinic ray or radiation drawing apparatus and heating, developing, rinsing and drying.

Examples of the alkaline developer of the positive resist composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, ethylamine, and n-propylamine. Primary amines, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, An aqueous solution of alkalis such as quaternary ammonium salts such as tetraethylammonium hydroxide and choline, cyclic amines such as pyrrole and piperidine, and the like can be used. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution.
Among these alkaline developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and an aqueous solution of choline are more preferable.
The alkali concentration in the alkali developer is usually 0.1 to 20% by mass, preferably 0.2 to 15% by mass, and more preferably 0.5 to 10% by mass.
The pH of the alkaline developer is usually 10.0 to 15.0, preferably 10.5 to 14.5, and more preferably 11.0 to 14.0.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, the content of this invention is not limited by this.

1. Synthesis Example 1 (Synthesis of Resins (A-2) to (A-6))
10.97 g (0.04 mol) of 5- [2,2-bis (trifluoromethyl) -2-hydroxyethyl] bicyclo [2.2.2] hept-2-ene (manufactured by Central Glass Co., Ltd.) and 2-methyl 17.30 g (0.06 mol) of adamantyl-α-CF ₃ acrylate (manufactured by Tosoh Corporation) was charged into the reaction vessel, and the reaction system was purged with nitrogen, and then the polymerization initiator V-65 (manufactured by Wako Pure Chemical Industries) was changed to 0. .248 g (0.001 mol) was added, and the mixture was heated and stirred at 65 ° C. while flowing nitrogen through the reaction system. Two hours later, 4 hours, 6 hours, and 8 hours later, 0.248 g of V-65 was added, and the mixture was heated and stirred for a total of 20 hours. Thereafter, the mixture was cooled to room temperature, and the reaction solution was dropped into 2 L of hexane. The powder was taken out by filtration and dried under reduced pressure at 50 ° C. to obtain 14.10 g of powder (resin (A-1)). The obtained powder had a weight average molecular weight of 8,800 and a dispersity of 2.21 as determined by gel permeation chromatography (GPC).
Resins (A-2) to (A-6) were obtained in the same manner except that the monomer to be added was changed. The monomer composition ratio, weight average molecular weight, and dispersity of each resin are summarized in Table 1.

2. Synthesis Example 2 (Synthesis of comparative resin)
Nippon Soda VP15000 (100 g) and propylene glycol monomethyl ether acetate (PGMEA) (400 g) were dissolved in a flask, distilled under reduced pressure, and water and PGMEA were distilled off azeotropically.
After confirming that the water content was sufficiently low, dihydropyran (11.0 g) and p-toluenesulfonic acid (0.02 g) were added and stirred at room temperature for 1 hour.
Triethylamine (0.03 g) was added to the reaction solution to stop the reaction, water (400 ml) and ethyl acetate (800 ml) were added and separated, and further washed with water, and then distilled off under reduced pressure to remove ethyl acetate, water, azeotrope. Minutes of PGMEA was distilled off to obtain a comparative resin (30% PGMEA solution) for KrF excimer laser exposure. The obtained resin had a weight average molecular weight of 16,600 and a dispersity of 2.15 as determined by gel permeation chromatography (GPC).

3. Synthesis Example 3 (Synthesis of nonafluorobutanesulfonic acid (p-hydroxyphenyl) diphenylsulfonium)
Nonafluorobutanesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium 48.4 g (0.1 mol) and nonafluorobutanesulfonic acid 3.0 g (0.01 mol) are dissolved in methanol and heated under reflux (70 ° C.). For 6 hours. After completion of the reaction, the reaction solution was distilled under reduced pressure to obtain an oily product. This oily product was washed twice with 100 g of ether, and 54 g (crude yield) of a product obtained by deprotecting the p-tert-butoxy group (nonafluorobutanesulfonic acid (p-hydroxyphenyl) diphenylsulfonium). 93%).

4). Synthesis Example 4 (Synthesis of acid generator (B-1))
54 g of the oily product obtained in Synthesis Example 3, 20.7 g (0.15 mol) of anhydrous potassium carbonate, and 18.1 g (0.12 mol) of tert-butyl chloroacetate were dissolved in 400 g of acetone and heated under reflux (60 For 3 hours. After completion of the reaction, the resulting inorganic salt was filtered, and the resulting organic layer was distilled off under reduced pressure to obtain an oil. The oily substance was subjected to column chromatography to isolate 50.4 g (yield 73% (two steps)) of compound (B-1).

5). Synthesis Example 5 (Synthesis of acid generator (B-2))
The deprotection reaction is performed in the same manner as in Synthesis Example 3 except that bis (p-tert-butoxyphenyl) phenylsulfonium nonafluorobutanesulfonate is used as a raw material, and nonafluorobutanesulfonic acid is obtained as an oily product. Bis (p-hydroxyphenyl) phenylsulfonium was obtained. Then, this was made to react by the method similar to the synthesis example 4 mentioned above, and the compound (B-2) was obtained.

6). Synthesis Example 6 (Synthesis of acid generator (B-3))
An acid generator (B-3) was obtained in the same manner as described in Example 1 of JP-A-6-287174.

7). Synthesis Example 7 (Synthesis of acid generator (B-4))
54 g of the oily product obtained in Synthesis Example 3 was dissolved in 30 ml of anhydrous methylene chloride, and this solution was placed in an ice bath and brought to 0 ° C. To this, 4.48 g (0.187 mol) of sodium hydride was added, and further 13.2 g (0.14 mol) of chloromethyl ether was added dropwise. Then, it stirred at 0 degreeC for 10 hours. After the reaction, 50 ml of water was added to the reaction solution to perform ether extraction. The mixture obtained by ether extraction was subjected to column chromatography to obtain 44.5 g (yield 70% (two steps)) of compound (B-4).

8). Synthesis Example 8 (Synthesis of acid generator (B-5))
54 g of the oily product obtained in Synthesis Example 3 was dissolved in 30 g of anhydrous tetrahydrofuran, to which 26.1 g (0.140 mol) of 2,2-dimethylpropanoic anhydride, 14.2 g (0.140 mol) of triethylamine, DMAP 0.9g (0.009mol) was added, and it stirred at room temperature for 5 hours. After the reaction, water was added to the reaction solution to perform ether extraction, and the mixture obtained by ether extraction was subjected to column chromatography to obtain 47.7 g (yield 75% (two steps)) of compound (B-5). Obtained.

9. Synthesis Example 9 (Synthesis of acid generator (B-6))
54 g of the oily product obtained in Synthesis Example 3 was dissolved in 30 g of anhydrous tetrahydrofuran, and 75 g (0.467 mol) of hexamethyldisilazane was added thereto, followed by stirring at room temperature for 24 hours. After the reaction, water was added to the reaction solution to perform ether extraction, and the mixture obtained by ether extraction was subjected to column chromatography to obtain 48.1 g (yield 74% (two steps)) of compound (B-6). Obtained.

10. Synthesis Example 10 (Synthesis of acid generator (B-7))
Nonafluorobutanesulfonic acid (p-tert-butoxyphenyl) phenyliodonium 65.2 g (0.1 mol) and nonafluorobutanesulfonic acid 3.0 g (0.01 mol) were dissolved in methanol and heated under reflux (70 ° C.). For 6 hours. After completion of the reaction, the reaction solution was distilled under reduced pressure to obtain an oily product. This oily product was washed twice with 100 g of ether and 41.7 g (crude crude product of nonafluorobutanesulfonic acid (p-hydroxyphenyl) phenyliodonium) from which the p-tert-butoxy group had been deprotected. Yield 70%). Subsequently, 14.5 g (0.10 mol) of anhydrous potassium carbonate, 15.8 g (0.10 mol) of tert-butyl chloroacetate and 300 g of acetone were added to this product, and the mixture was reacted under heating under reflux (60 ° C.) for 3 hours. . After completion of the reaction, the resulting inorganic salt was filtered, and the resulting organic layer was distilled off under reduced pressure to obtain an oil. This oily substance was subjected to column chromatography to isolate 35.5 g (yield 50% (two steps)) of compound (B-7).

11. Synthesis Example 11 (Synthesis of acid generator (B-8))
As a starting material, 60.7 g (0.1 mol) of nonafluorobutanesulfonic acid (1- [2- (4-tert-butoxyphenyl) -1,1-dimethyl-2-oxo-ethyl] -tetrahydro-thiophenium) was used. The acid generator (B-8) was obtained in a yield of 23.3 g (yield 35%) in the same manner as in Synthesis Example 10 except that it was used.

Examples 1-42 and Comparative Examples 1-3
(Preparation of resist composition)
A solvent was mixed with a solid component consisting of 1.00 g of the resin shown in Table 2 below, 100 μmol of a photoacid generator, 10 μmol of an organic basic compound, and 100 ppm of a surfactant so that the solid concentration was 7% by mass. Filtered through a 1 μm microfilter, positive resist compositions of Examples 1-42 and Comparative Examples 1-3 were prepared. In Table 2, the ratio indicated by the multiple use of the photoacid generator is a molar ratio, and the ratio indicated by the multiple use of the solvent is a mass ratio.

In addition, the symbol about each component in the said Table 2 means the following.
PAG-1: Triphenylsulfonium nonaflate PAG-2: Diphenyliodonium triflate E-1: Hexamethylenetetramine E-2: 1,5-diazabicyclo [4.3.0] -5-nonene E-3: 1 8-Diazabicyclo [5.4.0] -7-undecene E-4: Diethanolamine D-1: Megafac F176 (manufactured by Dainippon Ink & Chemicals, Inc.) (fluorine-based)
D-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
S1: Propylene glycol monomethyl ether acetate S2: Propylene glycol monomethyl ether

(Evaluation of sensitivity and dissolution contrast)
Each positive resist composition described above was applied onto a silicon wafer subjected to hexamethyldisilazane treatment by a spin coater, and the wafer was heated and dried at 120 ° C. for 60 seconds to form a 0.1 μm resist film. For this resist film, a 157 nm laser exposure / dissolution behavior analyzer VUVES-4500 (manufactured by RISOTEC JAPAN) was used to evaluate the sensitivity and dissolution contrast by 157 nm exposure.
The sensitivity here means that after exposure, the wafer is heated and dried at 130 ° C. for 90 seconds, developed using a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, and rinsed with pure water for 30 seconds. The film thickness is measured after being dried, and the minimum exposure amount at which the film thickness becomes 0 is indicated.
The contrast here refers to the slope (tan θ) of the exposure dose-dissolution rate curve.

(Depending on the number of development defects and density)
Each resist composition described above is applied onto a 6-inch silicon wafer coated with 65 nm of DUV-30J manufactured by Brewer Science Co., Ltd. using a spin coater, and heated on a vacuum contact hot plate at 120 ° C. for 90 seconds. The resist film having a film thickness of 0.15 μm was obtained by drying. The obtained resist film was subjected to image exposure using a KrF stepper (FPA-3000 EX5, NA 0.60) manufactured by Canon Inc., post-heated at 130 ° C. for 90 seconds, and then 0.262N TMAH aqueous solution. The number of development defects and the dependence on density were evaluated from the resist pattern obtained by developing the film.

The number of development results here refers to the resist pattern obtained as described above, the number of development defects is measured by KLA-2112 machine manufactured by KLA-Tencor Corporation, and the obtained primary data value is determined as the development defect. It was a number.
Furthermore, the obtained resist pattern was observed with a scanning electron microscope, and the following evaluation was performed. The line width of the isolated pattern of 0.150 μm is set to the side length (L1) with the same exposure as that for reproducing the mask pattern of 0.150 μm (line / space = 1/1), and the variation rate from 0.150 μm (0.150−L1) × 100 / 0.150 (%) was used as an index of density dependence. The smaller the value, the smaller the density dependency and the better.
The evaluation results are summarized in Table 2 above.

  From Examples 1 to 42 and Comparative Example 1 in Table 2, it can be seen that the composition of the present invention has improved sensitivity and dissolution contrast, and reduced development defects and density dependency. Furthermore, from the comparison between Comparative Examples 2 and 3, the photoacid generator used for the comparative resin for KrF excimer laser is changed from (PAG-1) to (B-1) to improve sensitivity and dissolution contrast. Although the effect is seen, it can be seen that the development defect and the effect of improving the density dependency are not seen.

Claims (5)

(A) a resin having a fluorine atom, decomposed by the action of an acid and increased in solubility in an alkaline developer, and
(B) A positive resist comprising a compound that generates an acid upon irradiation with actinic rays or radiation, wherein the compound (B) has a group that is decomposed by the action of an acid. Composition. 2. The positive resist composition according to claim 1, wherein the group (B) that decomposes by the action of an acid is any of an ester group, an acetal group, a ketal group, and a trimethylsilyl ether group. Stuff. 2. The positive resist composition according to claim 1, comprising a compound represented by the general formula (A), (B), or (C) as the compound (B).

In the above general formulas (A) to (C),
R ¹ represents an acid-decomposable group.
R ² represents an alkyl group, a cycloalkyl group or an aryl group.
R ³ represents an alkyl group, a cycloalkyl group, an alkoxy group, a nitro group, a halogen atom, an alkyloxycarbonyl group or an aryl group. At least two or more of R ³ may be bonded to form a ring structure.
R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an aryl group.
A ¹ represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group, an arylene group, or —O—R ⁶ —. R ⁶ represents an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.
A ² represents a single bond, an alkylene group, a cycloalkylene group, an alkenylene group or an arylene group.
Y ¹ and Y ² each independently represents an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group. Y ¹ and Y ² may combine to form a ring.
Z ⁻ represents a counter anion.
n represents an integer of 1 to 3. m is 1 or 2. p represents an integer of 1 to 5. q represents an integer of 0 to 4. However, 0 <p + q ≦ 5. The positive type according to any one of claims 1 to 3, wherein the resin (A) contains at least one repeating unit represented by any one of the following general formulas (I) to (IV). Resist composition.

In general formula (I),
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
Rk ₁ , Rk ₂ and Rk ₃ each independently represents a halogen atom, an alkyl group or an alkoxy group.
la represents an integer of 0 to 2, lb represents an integer of 0 to 6, and lc represents an integer of 0 to 6.
L ₁ represents a single bond or a divalent linking group.
n represents 0 or 1.
Y represents a hydrogen atom or an organic group.
In general formula (II),
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
R ₃₈ to R ₄₀ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group, an aryl group, an alkoxy group or an aralkyl group.
L ₂ represents a single bond, an oxygen atom, a sulfur atom or a divalent alkylene group.
Y represents a hydrogen atom or an organic group.
m and n each independently represents 0 or 1.
In general formula (III),
R _1a represents a hydrogen atom, a fluorine atom, a hydrogen atom, a bromine atom, a cyano group or a trifluoromethyl group.
R _{11 to} R ₁₆ each independently represents a hydrogen atom, a fluorine atom or a fluoroalkyl group. However, at least one of R _{11 to} R ₁₆ represents a fluorine atom or a fluoroalkyl group.
Y represents a hydrogen atom or an organic group.
na represents an integer of 1 to 5. When na is 2 or more, two or more R _{11 to} R ₁₆ and Y may be the same or different.
In the general formula (IV), R ₂₃ , R ₂₄ and R ₂₅ may be the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, a fluoroalkyl group or an alkoxy group.
Y represents a hydrogen atom or an organic group. n represents 0 or 1. A pattern forming method comprising: forming a resist film from the positive resist composition according to claim 1; and exposing and developing the resist film.